1. Field of the Invention
The present invention relates to a device for fining bubbles of gas contained in liquid.
2. Description of the Prior Art
Production of fine bubbles of gas contained in liquid has been desired particularly in a water purification plant, a swimming pool, a manure handling and disposing shed, etc. for improving the dissolving efficiency of ozone gas into water to be purified such as a sewage and a waste water.
In order to produce fine bubbles of gas, there has been proposed a system to use an air intake valve disposed on an inlet side of a pump which is provided in a pipeline for pumping water to be treated. With this conventional measure, the gas is mixed with the water at an inlet of the pump and is then forced to form bubbles by the stirring force applied by impellers of the pump.
Another prior art device for producing fine bubbles of gas comprises an air intake valve and a baffle plate both provided on an outlet side of a pump. With this device, water mixed with the gas or air on the outlet side of the pump collides with the baffle plate, so that the air is forced to form bubbles by the colliding force. Such a system using this device is called "ejector system".
However, with the prior art devices, the formation of the bubbles relies merely upon the stirring force applied from the impeller or the colliding force to the baffle plate, and therefore, the bubbles produced by these devices still have a relatively large diameter and may not provide a satisfactory result. For this reason, these devices have never been practically used for treatment of water in the water purification plant, the swimming pool, and the manure handling and disposing shed described above, where the water is required to be treated by a great flow rate per hour.